The present application refers to a slide valve of the type having a valve body and a valve plate which can slide transversely to the direction of flow of the medium and includes valve passages, and which cooperates with a counterpart which likewise includes passages which can be opened or closed by the valve plate.
The cooperating parts of the valve have as a rule been manufactured from metal ( U.S. Pat. No. 3,159,177), yet metals are subject to relatively high wear.
In order to avoid this disadvantage it is known of making the cooperating faces more resistant by their obtaining a ceramic coating by plasma-coating (see the brochure "Jordan Valve--Sliding Gate Control Valves", page 4, right-hand column, section "Jordanic"). The plasma-coating is a difficult process which demands a plurality of working steps not only for the application of the coating but also for the finishing in order to impart to the passages which have been partially closed during the coating the precise size and shape.
The object of the present invention is to construct a slide valve of the kind mentioned initially, in such a way that the cooperating closure parts are resistent to wear and are nevertheless simple and favorable in cost to produce.